Sound-box for talking-machines.



PATENTED JUNE 9, 1908.

APPLICATION FILED 00T.7, 1907.

lNVENTOR WITNESSES: of fizw yZizb ATTORNEY UNITED STATES PATENT OFFICE.

THOMAS KRAEMER, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO HAWTHORNE 6:

SHEBLE MANUFACTURING COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A CORPO- RATION OF PENNSYLVANIA.

SOUND-BOX FOR TALKING-MACHINES.

To all whom it may concern:

Be it known that I, THOMAS KRAEMER, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented a certain new and useful Improvement in Sound- Boxes for Talking Machines, of which the following is a specification.

This invention relates to sound-boxes for talking machines and has reference more particularly to the construction of the diaphragms for such sound-boxes.

The object of the invention is to effect certain improvements in the construction of such diaphragms to the end that a greater volume of sound is obtained in reproducing a record and that a more faithful reproduction is obtained as a result of the elimination of false sound vibrations.

I have illustrated the preferred embodiment of my invention in the accompanying drawings, in which Figure 1 is a front view of a sound-box, Fig. 2 is a central section of the same, and'Fig. 3 is an enlarged sectional view of the diaphragm alone.

Referring to these drawings, the soundboX is shown as having a main wall 1, a tubular extension 2 leading therefrom for conne'ction to the sound-conveying tube, and a circular flange 3 at the outer edge of wall 1 forming the outer wall of the box. Fitting snugly within wall 3 is a rubber strip or ring 4, circular in cross-section, forming a support for the diaphragm 5, this ring being retained in position by a circular ridge 6 integral with and rising from the wall 1. The stylus-lever 7 is pivotally mounted upon the wall 3, bears at its inner end upon the central portion of the diaphragm, and at its outer end is provided with an o. ening to receive a stylus 8, the latter being old in its opening by a setscrew 9. In the present instance, I have shown the stylus-lever as provided with notched lugs 10 adapted to receive knifeedges formed on a sheet-metal piece 11 which is secured to wall 1 and whose end forms a spring 12 tending to rock the stylus-lever on its knife-edge pivot in the direction to hold its inner end against the diaphragm.

The method of mounting the diaphragm herein shown with its edge bearing on a rubber ring has proven highly efiicient as the rubber absorbs counter-vibrations and thus Patented June 9, 1908.

Serial No. 396.135.

makes the reproduced sound much more clear. The diaphragm, which is a disk of thin sheet-metal, is of a diameter but little less than the internal diameter of the circular flange 3 and when in proper position it rests upon the rubber ring 4 with its outer edge separated from the interior wall of flange 3 by a narrow space entirelyaround the diaphragm. It is difficult, however, to get the diaphragm in this position every time it is inserted and to retain it there during long periods of use of the sound-box and if the diaphragm becomes moved out of this position the small amount necessary to carry its edge into contact with the flange 3, the vibrations of the diaphragm will be transmitted to the sound-box and the reproduced sound will be much less clear and distinct. I therefore provide means for centering the diaphragm in position and holding it against such movement as would cause its edge to engage the wall of the box. This is accomplished by providing a circular rib 13 in the diaphragm concentric with and close to the outer edge thereof, such that when the diaphragm is in position, this rib will coact with the rubber ring 4 to obstruct movement of 'the diaphragm in the plane in which it lies.

In Fig. 2 of the drawings, it will be seen that the rib 13 is in coaction with the ring 4 and would preclude'movement of the diaphra m in a vertical direction and that when in this position the edges of the diaphragm are separated from the wall of the soundboX. So long as the diaphragm is held in thisposition, the danger of transmitting the vibrations thereof to the walls of-the soundbox is eliminated.

In diaphragms for sound-boxes as heretofore constructed, especially those which are flat disks, the vibrating area is small and therefore the air-pressure behind the diaphragm is also small. In accordance with my invention, I construct the diaphragm in such manner that the area of vibration is considerably increased. This is accomplished by pressing a comparatively large portion of the dia hragm at its center out of the plane thereo so that the central portion of the diaphragm swells out to one side. This is shown in Figs. 2 and 3, from which it will be seen that the center 14 of the diaphragmis dis )laced from the plane of the edge portion thereof. The inclined portion 15 lll(' oining the center 14 and the edge portion udes a considerable partof the total area of the diaphragm and when the stylus-lever inclined portion is caused to vibrate so that a vibrating area is obtained which is considerably larger than that obtained when a flat disk is employed as a diaphragm. This increased area of vibration results in increased air-pressure behind the diaphragm and both of these combine to give a considerably increased volume of reproduced sound.

The diaphragmabove described may be pressed to the desired shape from a disk of sheet-metal and may therefore be manufactured at \'er low cost. metallic button to is preferably secured to the center of the din )hragm on which the inner end of the stylus-lever bears.

Having now described my invention, what I claim as new therein and desire to secure by Letters Patent is as follows 1. The combination of a sound-box having an outer wall, a resilient member within said wall, and a diaphragm supported on said member with its edge out of contact with said wall, said diaphragm having a rib therein coacting with said member to prevent movement of the diaphragm in the plane in which it lies, substantially as set forth.

2. The combination of a sound-box having an outer wall, a rubber ring Within said wall, a ridge on the sound-box to retain said ring in position, and a diaphragm supported on said rin with its edge out of contact with said walT, said diaphragm having a rib therein close. to its outer edge coacting With said member to prevent movement of the diaphragm in the plane in which it lies, substan tially as set forth.

3. The combination of a sound-box having a wall and shaped to provide a surface within the box adjacent to said wall for supporting a diaphragm, and a diaphragm supported on said surface, said diaphragm having a rib therein coacting with a part of the box structure to preclude movement of the diaphragm in the plane in which it lies to carry its edge into engagement withsaid wall of the box, substantially as set forth.

This specification signed and witnessed this day of Septr., 1907.

THOMAS KRAEMER.

Witnesses H. MEIER, II. M UHLSCHLEGEL. 

